Manufacture of piston rings and the like



April 9, 1935. w. A. OUBRIDGE 1,997,534 MANUFACTURE OF PISTON RINGS ANDTHE LIKE Filed Mama 5, 1954 PatentedApr. 9, 1 v v I Q i l,

WllliamArthurOubridgmQoientrn-Eng ,apni qatmammas,]-m4,fserlali-zt.m,iar,J l mc w 'n aw amaph v (Giles-15th:) H v'Ihlsinventionrelates tothejmanuiacture'oilongitudinallyatdacrossannular sawlcuts i piston and like-rings, from acylinder or lpot" ,to-iorm thetgap and subs uently expanded or and hasioritsiobject to'provide nej or improved distendedbytheinse'rtioninthegapfotaspacing methods of producing rings tothe-selectedcurve stripe as showrrinFigure 3,so as to causethepot 6hereinafter defined, in, which, duringtheprocess to assumeincross-.section the shape o! the selectof heatrtorming or oi hardening,the rings-are ed curve aforesaid; v-- 'i'hepotis then exposedtoprevented from becoming distorted out of their the action 01 heat tosetit in its expanded form own-plane. p i i after which thespacing strip eis removed when 7 It is known thatit a circular ring split transtheformed rings 'can be readily separated by 10 verselyat one point, isexpanded at the split-in a breaking them apart or by machining outthebore l0 circumferential direction and heated so as to set of the potso thatthe rings fall apart. i the ring in its expanded state it willexert a' uni- In the alternative case where the pot isturned formoutward pressure when compressed within a or heat formed in the firstinstance to theshape cylinder. The shape of such a ring when in its ofthe selected curve,it is saw-cut annularly as free and unstressed stateis that of an involuteoi above described toiorm the rings and either cut15 a cycloid and is referred to throughout this speciwith a longitudinalgroove 1 Figure 1, equal to iication as the selected curve. v i widthto-the open gap 01 an unstressed piston In the manufacture ofpistonrings as atpresring, or with-two longitudinalsawcuts 0',11,;E'igent carried out the process of heat-iorming or ure'5,.atadistance irom each other equal to the hardening has been effected afterthe rings have width of the said open gap, the depth otthe groove 20been severed from the pot,lthe loose rings,: aror the cuts beingslightly less thanthefull radial ranged in stack iormatiombeingcl'ampedbatw'een thicknessoi the pot, so that after the pot has a pairof plates to keep them in plane alignment. heat treated the metal at thebottom of the groove;

The improved method of manufacture of pisor between thelongitudinalcuts, can be knocked ton and thelike rings to the selected curveacoutand the rings separated from each other; 25. cording to thisinventiondispenses withthe need The longitudinal cuts can be made by asaw, a i for clamping platestand is characterized in that cuttingflameorby suitable means. the heat-forming or hardenirigfprocess iscarried I claimze 6 out after the rings are formed in the potlbu'tbe 1.The methodo! manufacture of piston rings tore they are parted therefrom;Bythis meansfrom a cylindricalp'otwhich consistsin 30 the rings areeflectually prevented from becoming a series oi annular saw cuts in thepon -slotting distorted outot their own plane. the pot throughlongitudinally across the saw In the accompanyingdrawing, cuts,expanding the pot by the insertion 01 a Figure 1 shows aportion of a potin which the spacing strip inthe slot, heating the'pot to. set V ringsare formed. v v it in its expanded form, removing the spacing-- 5 Figure2 i an nd v e of the sa ei i strip, and separating th indlvidualringsformed Figure 3 shows the pot expanded to the form by the annular sawcuts." i v the selected curve. L i 2. The method of manufacture ofpiston. Figure! is a cross-sectional view or spot illusfrom a potwhichfconsists' in forming the 40 trating an a ter ativ t o f-pmd n 1 8the selected curve, making a series of annular 4a to the selected curve.saw cuts in the pot, cutting a longitudinal groove r Figure 5 is adetail view showing an alternative in the pot equal in width to the,opengap of an methodpf forming the gap. l v. i i ,unstressedflpistonring, and of adepth slightly 7 The cross-sectionaliorm of thepotaaiterbeless than theflthickness of the wall'oi the pct,

mg turned to the required diameter-may either be heating the; pot forhardening purposes, remov 45 i l as Shown in Figure 2, i the l 015 mg'theibottom of the groovetand separating the the selected curve asrepresented in Figure 4. q, individual ringsltprmed by therannular sawcuts.

In either case the rings b are formed in the pot l 3. The method oinnanuiacture of piston rings y makin SBrie 0f annul r aw cuts C,'Wh1h iroma pot'which consistsuin forming the pot ta are preferably substantiallynarrower thanthe. "thej selectedcurve, making a series ot annular 5 Irings themselves, the sawing operation being iaw cuts'hin the pot,cutting. two longitudinal stopped short of actually severing the ringsfromv in the pot at, a distancexfromeach other i the pot, asseenin-Figure 1:; I to the widthrot the open gap; 011% un- Where, asrepresented in Figures. 1 2,1 the stressed piston ring and .ot' a depthslightlgigless' pot is or circular cros ion it e' etisdthi' flzk than.the h W the Pmmesm? i material or the potvbetwaen" severed from saidcurve the potter ha purposes, removing the strip/of metal between thelongitudinal grooves? and separating individual ringsformediby saw r"adjacent ring, por "tions in a radial'direetion form an annularglfmveaf substantially depth ina radial directioniazylk leave a thin-webconnecting said portions. and giving s id flngfpor-"tionacxflms-partiallysevered from the pot the severed from thepot.

.5. The method of. manufacture of piston rings from a pot, comprisingmaterial of the pot between adjacent ring portions .in a radialdirection to'form an annular groove between adjacent ring portions ofsubstantially uniform depth in a radial direction and to leavea t [webconnecting said ring portions, giving "said ringportions thus partiallypot the selected curve, and

subsequently heat-treating-the pot before the portions are completelyseveredtherefromr manufactureof piston rings 6. Themethod of limiter aradial direction to leave a thin web before the are completelyheat-treating the partially removingtthe pletely severed therefrom tofrorna pot, comprising partially removing the of the pot betweenadjacent ring porpartially severed therefrom to the shape of theselected curve, and subsequently heat-treating the pot before the ringportions are severed therefrom.

7. The method of manufacture of piston rings from a pot, comprisingpartially removing the material between vadjacent ring portions of apot'ha'ving the selected curve, and subsequently pot before the 88 arecompletelysevered from the pot.

8. The method of manufacture of piston rings from a pot, comprisinggiving said pot prior to setting heat-treatment the. selected curve,par-.

tially removing in a radial direction the material of the pot betweenadjacent ring portions thereof prior t'o'setting heat-treatment, andsubsequent. to both of the foregoing'steps heat-treating the pot beforethe ring portions are comset such ring portions in such selected curve.7 1 I V ARTHUR OUBRIDGE.

